Judges at the European court of human rights. A lawyer representing Privacy International said the court must consider 'whether the current darkness in which GCHQ operates is allowed to continue'. Photograph: Vincent Kessler/Reuters

The secret "Five Eyes" treaty that authorises intelligence sharing between the UK, US, Australia, Canada and New Zealand should be published, according to an appeal lodged on Tuesday at the European court of human rights.

The application by Privacy International (PI), which campaigns on issues of surveillance, to the Strasbourg court is the latest in a series of legal challenges following the revelations of the US whistleblower Edward Snowden aimed at forcing the government to disclose details of its surveillance policies.

The civil liberties group alleges that the UK is violating the right to access information by "refusing to disclose the documents that have an enormous impact on human rights in the UK and abroad".

PI says that it has exhausted all domestic legal remedies because its freedom of information request for the document, detailing how the UK's security services collaborate with the National Security Agency (NSA) in the US and other foreign intelligence agencies, met with outright refusal.

"The UK government's GCHQ monitoring service invoked a blanket exemption that excuses it from any obligation to be transparent about its activities to the British public," said PI.

Eric King, deputy director of PI, said: "More than a year after Snowden, the British government continues to dodge the question of just how integrated the operations of GCHQ and NSA truly are. Key documents like the Five Eyes arrangement remain secret, despite them being critical to proper scrutiny of the spy agencies.

"The hushing-up of the extent of the alliance is shameful. The public deserve to know about the dirty deals going on between the Five Eyes, who trade and exploit our private information through this illicit pact. For trust to be restored, transparency around these secret agreements is a crucial first step."

Rosa Curling, of the law firm Leigh Day, which represents PI, said: "The UK's Freedom of Information Act precludes government authorities from disclosing to the public information directly or indirectly supplied by GCHQ.

"This absolute exemption is unlawful and contrary to article 10 of the European convention on human rights, which provides for the right to freedom of expression, which includes the right to receive information.

"It cannot be correct that all information, without exception, directly or indirectly supplied by GCHQ is exempt from public disclosure. With the credibility and public confidence in the activities of the UK's secret service at an all-time low, it is crucial that the [Strasbourg] court considers whether the current darkness in which GCHQ operates is allowed to continue."